Urinary stones include stones existing in a urinary tract such as a kidney, a ureter, a bladder, a urethra, and the like, and a calculus generated in a kidney or in a ureter is referred to as an upper urinary stone. In urinary tract stone disease, various symptomatic states are caused by these urinary stones. For example, in the case where a calculus generated in a kidney is moved to a ureter, the calculus damages the ureter and causes a pain or blood in the urine, or the calculus blocks the ureter, so that a transient hydronephrosis state is generated, and hence an acute pain (colic pain) from a lower back to a lateral region may result. In order to alleviate or treat these symptoms, removal of the calculus is effective means.
In the urinary tract stone disease, if effects such as natural stone drainage and a conservative medical treatment cannot be expected, a surgical positive removal method is performed. Examples of the positive removal method include mainly an Extracorporeal Shock Wave Lithotripsy (ESWL), a Transurethral Resection of Lithotripsy (TUL or URS), and Percutaneous Nephrolithotripsy (PNL or PCNL). Examples of the TUL include an r-TUL (or r-URS) in which a hard renal pelvis ureter mirror (hereinafter, referred to as a hard mirror) is used, and an f-TUL (or f-URS) in which a soft renal pelvis ureter mirror (hereinafter, referred to as a flexible ureteroscope) is used. In a TUL, a calculus in a ureter or a renal pelvis and renal calyx may be directly reached extracorporeally, transvesically, or ureterily by using a hard mirror or a flexible ureteroscope so that the calculus may be directly broken or extracted. Therefore, advantages such that damage to a ureter, a kidney, or the like may be suppressed more and a high stone free rate may be realized in comparison with the ESWL or PNL are achieved. As an apparatus used in the TUL, an apparatus configured to remove a calculus generated in the ureter or the kidney or a plurality of broken calculus pieces generated after having broken the calculus by a laser to the outside of the body while retaining the same with a wire (basket forceps) is known. An example is disclosed in Japanese Application Publication No. 2001-512355.
The extraction of the stones by using the basket forceps is limited in gripping function of the basket forceps or the size of a ureteral lumen or a ureteral access sheath (guiding catheter), and hence the number of the calculi and the broken calculus pieces which may be removed in one operation is limited in a series of stone extracting operations from a step of gripping the broken calculus pieces to a step of carrying the gripped broken calculus pieces to the outside of the body with the basket forceps. Therefore, in order to remove the calculus, it is necessary to perform an insertion and a retraction of the basket forceps many times between the outside of the body and the position where the calculus exists. Accordingly, a user (operator) bears a heavy burden. In addition, various disadvantages for a patient occur such that a risk of, for example, developing an infection of a urinary tract or the like after the operation, and a burden to a ureter due to ischemia or the like generated due to a lengthening of an operation time for performing the insertion and the retraction of the basket forceps, and a risk of relapse increases because the calculi and the broken calculus pieces cannot be removed within a limited time of operation set for suppressing the infection after the operation.
By gripping a plurality of calculi, end surfaces of the calculi and the broken calculus pieces expose from a gap between metallic wires which constitute the basket forceps. Therefore, if an attempt is made to remove the plurality of calculi and the broken calculus pieces to the outside of the body at once, inner walls or the like of the kidney and the ureter may become damaged, or an end surface of an opening of a ureteral access sheath on a distal side and exposed portions of the calculi and the broken calculus pieces fit and hence cannot be pulled out to the outside of the body.